Coal-fired power plants are shutting down in record numbers, and it’s not completely clear if the electric grid will weather the shift without reliability problems or substantial rises in energy costs for consumers.­

Faced with competition from cheap natural gas and a slew of environmental regulations that will make production more expensive, 16 percent of coal-powered plants are expected to retire by 2020, many of them as soon as next year, according to the Energy Information Administration.

The vast majority of the plants slated to close are concentrated in the Midwest and mid-Atlantic, causing headaches for grid planners trying to make sure they have enough electricity on hand to meet high demand in winter and summer months.

The situation has become a constantly evolving challenge, as utilities and regulators try to figure out how to keep power flowing. On one hand, environmental advocates and natural gas proponents believe other resources will be able to step in and replace the coal plants. But the coal industry, as well as some regulators and vocal utilities, aren’t so sure. They say this winter’s extremely cold weather and strains on the electric system were an early warning sign that it will be difficult to meet power needs with fewer coal plants. READ THE FULL STORY.